Coastal Contractor News

Protecting the Shore: Can Man-Made Dunes Work Like the Real Thing?

For many shoreline communities in the path of Hurricane Sandy’s storm surge, sand dunes made a difference. The New York Times noted the effect in a December 3 story (“Resisted for Blocking the View, Dunes Prove They Blunt Storms,” by Mireya Navarro and Rachel Nuwer). “Up and down the coast,” writes the Times, “dune barriers acted like soft sea walls made of sand and vegetation that even when flattened or breached still managed to protect places like Westhampton Beach on Long Island, Plumb Beach in Brooklyn, and Bradley Beach in Monmouth County, N.J., by blunting the attack of surging waves and tides.”

In the storm’s aftermath, communities are pushing to have the federal government rebuild or improve their dunes. On New York’s Rockaway Peninsula, the U.S. Army Corps of Engineers says it will start work in June to build up beaches and dunes with sand dredged from nearby ocean bottom. “We’re getting sand and we’re getting sand very soon,” Corps project manager told citizens at a public meeting held on February 13. But residents want the work to start earlier, reports the New York Daily News, and they’re hoping for rock walls and jetties, not just dunes (“Rebuilt Rockaway beaches need more than a big dose of sand, locals say,” by Lisa L. Colangelo). One local described the planned Corps project as “a temporary fix, a Bandaid.”

While dunes do offer a measure of protection, scientists who study the problem say that man-made dunes may be less effective than natural dunes. NPR covered that issue in a February 15 report (“After Sandy, Not All Sand Dunes Are Created Equal,” by Adam Cole). Volunteers working with the New Jersey Department of Environmental Protection placed thousands of donated Christmas trees along a stretch of beach, intending to capture windblown sand and nurture a new dune, the network reported. But expert Norbert Psuty told NPR that piles of sand don’t make a dune, and that artificial dunes, even if augmented with grass and other vegetation, won’t last long if Nature wants to push the whole barrier island back toward the mainland.

Still, New Jersey offers some success stories of communities who have used low-tech methods to build and nurture barrier dunes — and who can credit those efforts with protecting their homes against Sandy’s surge. The Newark Star-Ledger offers an in-depth look at one such example in a “Ledger Live” video: the paper’s Brian Donohue compares the highly engineered beaches of Sea Bright, N.J. with the wind-formed dunes of Midway Beach in the South Seaside Park section of Berkeley Township (Ledger Live video: rebuilding New Jersey's beaches after Hurricane Sandy).

“While Sea Bright was devastated by Hurricane Sandy, Midway was unscathed,” the Ledger reports. Thirty years of patient community effort using low-tech wind fencing and Christmas trees has built a high dune in front of Midway’s set-back streets and houses that proved more resilient in the storm than expensive sea walls and machine-built dunes protecting other communities.